(178b) Dynamic Wetting Effect on 3-D Liquid Film Waving for CO2 Absorption Intensification

CO₂ capture has been increasing demand for global energy saving and environment protection. It is noticed that this chemisorption process in the two-phase contact system interact closely with flow behavior. Given most literatures focused on absorbent capability or Marangoni convection on gas-liquid interface, this work investigated solid substrate property and its effect on flow behavior and finally influenced the removal rate. To improve the chemisorption efficiency, we fabricated metal wire mesh as solid substrate on which absorbent solution film formed. MEA (monoethanolamine) with concentration of 15wt% was used as aqueous absorbent, and experiment showed that such solutions were well wetted on the surface of wire mesh substrate. To make comparison, smooth flat plate was adopted in the experiment and it manifested that on the flat plate, liquid drop showed clear triple-phase contact line between free surface and solid substrate. It was also illustrated by OCA15 facility the difference of contact line of liquids in static or slippage state.

Both experiment and numerical simulation indicated that dynamic wetting had great potential to change flow behavior. The results manifested that in good wetting case, liquid film was well spread; however in worse wetting, stagnation point was found in the middle of the flow region. Due to the flow behavior change, CO₂ capture rate can be increased by 2~3 times. Thus this fabricated wire mesh can be used as a novel structured packing for such chemisorption processes.

In the simulation model, three-dimensional liquid film structure is reported for the first time, and also combined with its chemisorption behavior. Drag force and surface tension were introduced into momentum equations as source terms in the computational fluid dynamic model. In this thin film contact process, interfacial turbulence was acquired its effect on component diffusion intensification. Dynamic wetting property was also considered in the flow model. 3-D liquid film images were illustrated to show how this fabricated wire mesh could intensify CO₂ capture.